Fans weren’t the only ones shocked by Red Bulls’ abrupt firing of popular head coach Mike Petke last Wednesday. The players were blindsided as well, waking up to the news from social media and texts.

Goalkeeper Luis Robles said he had spoken Monday with newly hired sporting director Ali Curtis, and went to bed Tuesday with no hint of the next morning’s impending coaching change that has sent the fanbase into revolt. After Petke was replaced with Jesse Marsch, billboards were bought nearby and a “town hall” meeting was called.

“The only thing we knew before was from social media, before Jesse being hired. When I went to bed, I didn’t know,’’ Robles told the Post.

“I woke up and I had no idea. … I don’t think anyone knew. … On Monday, I had a long discussion with Ali. Never did the coaching position come up, never did Mike’s name come up. He was talking about players, talking about himself. When I went to bed, that wasn’t anything that was on my mind.’’

Instead, Robles found out his coach was fired from Google.

“I woke up at 6:30 and my phone had a dozen messages. I went on the Internet, googled Mike Petke, and I saw,’’ said Robles. “I responded to the guys that were on the West Coast that had seen and texted me.’’

Fan favorite Petke – who played more games than anybody in MetroStars/Red Bulls annals – also coached the team to its first hardware, the 2013 Supporters’ Shield.

Unlike Rex Ryan dangling in the wind for almost half of the Jets’ season, the only thing more abrupt than Petke’s firing was Marsch’s official hiring a few hours later.

“I went into the arena to train, and I got a text from Ali: ‘When you’re done, come upstairs so I can introduce you to your new coach.’ I found out about a half-hour before the announcement went out,’’ Robles said. “I think that goes for most of the team.’’

The fan base instantly became unified against the move, coming together to rent a billboard on Route 280 denouncing the firing. Many called the front office demanding refunds on season tickets, and the Red Bulls hastily called a “town hall” meeting for Friday that will include Curtis and Marsch.

“I know there’s been a pretty negative reaction from the fans. I hope they can realize the players are still here, still working hard,’’ Robles said. “That’s our M.O., and hopefully we can have success.’’